戦務 is read as せんむ (semmu) and means service.
せんむ
semmu
せんとうにんむ
combat mission
いくさば
battlefield
せんご
postwar period
たたかい
battle
せんそう
war
せんぜん
pre-war days
せんしゃ
chariot
せんし
death in battle
せんりょく
ability (to compete)
せんじ
wartime
せんじゅつ
tactics
せんちゅう
during the war